Mishnayos Bava Metzia Perek 7 Mishnah 9

One wolf that approaches a flock and attacks is not considered a circumstance beyond one’s control, as the shepherd can drive it away, but an attack by two wolves is considered a circumstance beyond one’s control. Rabbi Yehuda says: At a time of wolf attacks, when many wolves come out of hiding and pounce on animals at every corner, even an attack by one wolf is considered a circumstance beyond one’s control. An attack by two dogs is not considered a circumstance beyond one’s control. Yadua the Babylonian says in the name of Rabbi Meir: If the two dogs came and attacked from one direction it is not considered a circumstance beyond one’s control, but if they attacked from two directions, this is considered a circumstance beyond one’s control, as the shepherd cannot protect his flock from both of them at once. If bandits came, this is considered a circumstance beyond one’s control. Likewise, with regard to an attack by a lion, a bear, a leopard, a cheetah, and a snake, these are each considered a circumstance beyond one’s control. When is an attack by one of the above considered beyond his control, which means that a paid bailee is exempt? It is when the dangerous beasts or bandits came of their own accord to the usual grazing spot. But if the shepherd led his flock to a place of groups of beasts or bandits, this is not considered a circumstance beyond one’s control, as he is at fault.

זְאֵב אֶחָד, אֵינוֹ אֹנֶס, שְׁנֵי זְאֵבִים, אֹנֶס. רַבִּי יְהוּדָה אוֹמֵר, בִּשְׁעַת מִשְׁלַחַת זְאֵבִים, אַף זְאֵב אֶחָד אֹנֶס. שְׁנֵי כְלָבִים, אֵינוֹ אֹנֶס. יַדּוּעַ הַבַּבְלִי אוֹמֵר מִשּׁוּם רַבִּי מֵאִיר, מֵרוּחַ אַחַת, אֵינוֹ אֹנֶס, מִשְּׁתֵּי רוּחוֹת, אֹנֶס. הַלִּסְטִים, הֲרֵי זֶה אֹנֶס. הָאֲרִי וְהַדֹּב וְהַנָּמֵר וְהַבַּרְדְּלָס וְהַנָּחָשׁ, הֲרֵי זֶה אֹנֶס. אֵימָתַי, בִּזְמַן שֶׁבָּאוּ מֵאֲלֵיהֶן, אֲבָל אִם הוֹלִיכָן לִמְקוֹם גְּדוּדֵי חַיָּה וְלִסְטִים, אֵינוֹ אֹנֶס: